Consumption of poultry in the United States and elsewhere has resulted in a substantial increase in waste products for disposal by poultry producers. In addition to feathers, components of the feather-waste stream include avian parts such as heads, wings, feet, and the like, collectively referred to as "avian parts or non-feather avian parts", are a significant part of the feather-waste stream. Commercial poultry producers lose a considerable part of their harvest during the feather-picking operation. Efficient recovery of this loss in not known to the art.
Disposal of the mixture of feathers and avian parts from the picking process is expensive and difficult. For example, poultry waste is burned or buried. These methods are environmentally unsound and restricted. A more expensive disposal method for poultry waste uses hydrolysis to produce a low-quality protein animal feed for which demand is low; it sells for a break-even cost or a loss. Beyond animal feed, there are no reports of commercially useful products manufactured from feather waste.
Recent strides have been made to develop processes for making a useful fiber material from feather waste in a commercially viable manner. Such processes present to poultry producers the ability to reduce waste disposal costs and to gain a profit from feather waste. Additionally, the conversion of feathers to fiber offers a more environmentally benign solution for feather disposal than former methods. Still further, it has been proposed to use the fiber recovered from feathers to produce articles that would otherwise usually be made of environmentally depleting resources or be made by methods that are more detrimental to the environment. An example is paper. Making fiber from feather waste provides less harmful alternative products and processes and thus generates benefits outside the poultry production industry as well as within.
Significant developments toward producing fiber from raw feathers were disclosed using the batch system described in U.S. Pat. No. 5,705,030, hereafter referred to as '030, the entire disclosure of which is hereby incorporated herein by reference. The '030 patent teaches a method comprising five essential steps, namely, (1) collecting raw feathers, (2) washing said feathers in a polar, water-soluble organic solvent, (3) repeating said washing step, (4) removing solvent from said feathers, and (5) removing fibers from feather shafts. It uses only one of the components from the feather waste stream, raw feathers.
Although the '030 patent represents an advance in the art, room remains for improvement. For example, the patent calls for washing the feathers two separate times in an organic solvent and does not include a closed continuous counterflow wash system. Reducing the amount of washing reduces operating costs and risks of environmental exposure to the solvent. It is desirable to reduce the amount of washing and thereby further reduce operating costs and risk of hazard from environmental exposure to the solvent.
The methods of stripping feathers from birds in poultry production often referred to as "picking" is of great practical significance to commercially successful conversion of feathers to fiber. In a typical feather picking unit operation, suspended bird carcasses are repeatedly struck by numerous, high-speed, flexible, finger-like beaters. In addition to feathers, the striking action frequently pulls parts from the birds, such as heads, necks, feet, and the like. These non-feather parts can not be returned to production and thus represent a substantial poultry production yield loss. Also, non-feather avian parts are usually combined with, and thus contaminate the feathers. This can render the feathers unusable, for example, because as mentioned, the '030 patent process calls for making fibers only from raw feathers. A process for converting feathers to fiber that can use raw feathers mixed with non-feather avian parts eliminates expensive manual or mechanical devices required to produce raw feathers specified in the '030 patent.
When avian parts are left in the feather waste stream, the yield of fiber, protein, and oil is maximized and the environment is relieved of unwanted nitrogen. Furthermore, a process which produces more fiber, protein, and oil is highly desirable.
Consequently, there is now provided according to this invention a process for converting components of a feather-waste stream to fiber, protein, and oil comprising the steps of
(a) contacting with a solvent said components selected of the group consisting of feathers and a mixture of feathers and avian parts from the feather-waste steam; PA0 (b) maintaining contact of said components of the feather-waste stream with the solvent; PA0 (c) drying said components of the feather-waste stream; PA0 (d) shredding and comminuting said components of the feather-waste stream; and PA0 (e) classifying the shredded and comminuted said components of the feather-waste stream. PA0 (a) accepts both avian feathers and a mixture of avian feathers and other avian parts; PA0 (b) eliminates the expense and difficulty of manual or mechanical removal of avian parts to produce raw feathers; PA0 (c) uses only a single contact with a water soluble organic polar solvent; PA0 (d) uses a lesser total quantity of extraction solvents than previous methods; PA0 (e) provides more efficient energy use than previous methods; PA0 (f) provides for more complete recovery of fiber, oil, and protein than previous methods; PA0 (g) channels avian parts from the waste stream to valuable end uses for novel products; PA0 (h) diverts unwanted nitrogen waste from the environment; PA0 (i) can restore a significant product loss from commercial avian processing operations.
This invention also provides the process for converting feathers and mixtures of feathers with other avian parts to fiber, protein, and oil comprising the steps (a)-(e) set forth above with the advantageous feature that only a single contact of the feather-waste stream with solvent is called for. Therefore, the two washing steps disclosed in the prior art can be condensed to one.
An important advantage of this invention is the solvent gradient which washes the feather-waste stream to make substantially completely devoid of residuals, impurities, and potentially detrimental microorganisms.
Another advantage of this invention is that the fiber product can be classified according to size to provide selected fiber fractions. The fiber fractions can be optimized for various end uses such as: filters; wovens and non-wovens; extrusions, laminates, and composites; fillers and insulation; packing and adsorbents; paper-like products; biodegradable horticultural pots, mats, and other matrices thereby increasing the value of the fiber product.
Protein and avian oil products, sometimes collectively referred to herein as "residuals", are also generated by the novel process. Upon subsequent processing, these residuals can be made into or be incorporated in useful products such as biochemical reagents, pharmaceuticals, cosmetics, animal feed and fertilizer. The added value of powdered protein obtained from residuals in accordance with the novel process will be high as a result of contribution from non-feather avian parts in the feather-waste stream. Consequently, the economic value of the powdered protein will be greater than heretofore produced by prior art processes in which only raw feathers are used.
There is further provided an apparatus useful for carrying out the process of this invention.
Thus, it is a primary objective of this invention to eliminate the expense and difficulty of removing non-feather avian parts from a poultry production feather-waste stream to produce raw feathers.
It is another objective to provide a continuous, counterflow process for converting the feathers-waste stream to fiber, protein, and oil that employs only a single contact of the feather-waste stream with an organic solvent.
It is yet another objective to provide a process for converting the feather-waste stream to fiber, protein, and oil that uses energy and solvents more efficiently than prior art methods. For example, little or no solvent is lost to the atmosphere from the closed system. Waste from solvent reclamation can be used as an energy source to generate heat, for drying, distillation, and the like.
Still a further objective is to provide a process for recovering a larger quantity of powdered protein from conversion of feathers to fiber than in prior art.
Another objective is to provide fiber, protein, and oil which have value in diverse utilities.
Additionally, it is an objective to recover significant products lost from commercial avian waste streams.
Accordingly, the advantages of this invention are it:
Therefore, the instant invention provides efficient procedures and useful products while solving an environmentally sensitive problem of waste disposal.